International Application number WO 93/03481, issued to Lasor Limited, GB, inventor: John Brian Baker, discloses a recording apparatus which uses a laser array and a lenslet array. The system has a collimator lens in front of the laser array and one lenslet array at an intermediate image plane. This collimator is required to have a high numerical aperture in order to collect the laser light. This system is primarily used with an array of single-mode diode lasers spaced 100 micrometers center-to-center operated at relatively low power. For a ten-channel recorder Bakers' total array size would be 1 mm. However, high power diode laser arrays are typically 10 mm long and the diodes are separated by typically 1 mm to reduce thermal cross-talk. A lens which collects the highly divergent laser beams over 10 mm of field is expensive and difficult to make. In addition, this system disclosed by Baker is not efficient as it does not have a field lens at the intermediate image plane and it does not address the serious problem of array deviation from straightness which is an inherent problem especially for large high power arrays.
U.S. Ser. No. 986,207, filed Dec. 7, 1992, discloses means for using diode laser arrays in multi-beam printers and recorders. These means include a lenslet array which has power in the array direction and converts the light from the laser array into a closely packed ensemble of printing spots, and includes means for collecting and shaping the beams in the cross-array direction.